‘Then there touched me again one like the appearance of a man, and he strengthened me. And he said, “O man greatly beloved, do not be afraid. Peace be to you. Be strong, yes, be strong.” And when he spoke to me I was strengthened, and said, “Let my lord speak, for you have strengthened me”.'
Again ‘the man' touched him and he felt renewed. Then he was again described as a man precious to God (compare Daniel 10:11), and told not to be afraid. Rather he was to be strong, repeated for emphasis (compare Joshua 1:6; Joshua 1:9). It basically means ‘you will need to be very strong'. And even as the ‘man' spoke to him he was strengthened, and asked the man to give to him the message that he had come to give. God often works through our weakness, but He strengthens us at the last.